Assessing The Habitat Suitability of Six Coniferous Forests Using Avian Assemblages At High Altitude Ecosystem

Birds are habitat specialist, i.e. often selects habitat that offers ample services such as a variety of food resources, safe breeding and less disturb sites to satisfy their needs. We aimed to ascertain the conservation status of avian assemblages inhabited in six different coniferous forests. The study employed the point count method to determine the avian assemblages in each forest type. The surveys were conducted employing the distance sampling point count method and determining the floristic composition through direct visual estimation from January 2018 to March 2019. In total, 2465 bird individuals representing 57 species and 29 families were observed in six coniferous forests. Twelve tree species, nine shrub species, and 14 grass species were identified in the forests. Except for the Streptopelia turtur (vulnerable), all bird species are listed as “least concern” according to the IUCN Red List Category and Criteria 2019–2. Notably, the relative abundance of bird assemblages among six coniferous habitats was significantly different (F5, 293 = 22.8, p < 0.05). The CAP results reflected that bird diversity indices varied coniferous forests. Strikingly, dry–temperate coniferous forest (BG) was densely populated (5.831 ± 0.694 birds•ha−1) as compared to other habitats. These findings suggested that subtropical coniferous forests are cradles of life for a wide array of avian assemblages and hence should be declared as protected forests to enhance avian assemblages in this region.

Nestedness structure of bird assemblages in a fragmented forest in Central Argentina: the role of selective extinction and colonization processes

Nestedness analysis constitutes an important tool to understand the processes that shape wildlife communities. It also allows a quick first evaluation of species extinction proneness in fragmented landscapes. Here, we tested whether avian assemblages in the fragmented Espinal forest exhibited nested subset patterns. Furthermore, we examined whether selective extinction or selective colonization are driving nested subset patterns. We studied avian assemblages in 13 forest fragments in central Argentina during breeding and non–breeding seasons. We completed partial Spearman rank correlations to explore the relationship between nestedness rank order and habitat patch variables and species life history traits related to species extinction proneness and colonization rate. Bird species showed strong nestedness patterns, both for the total incidence matrix and for forest fragments and species separately. Nestedness patterns were similar during the breeding and non–breeding seasons. The nested rank order of forest fragments correlated with area and distance to nearest fragment, both of which are patch characteristics known to increase the probabilities of species extinction. The nested rank order of species was correlated with the minimum area of species requirement, trophic guild, and range size, traits that are linked to extinction risk. Selective extinction processes rather than selective colonization appear to be driving nestedness patterns of bird assemblages in fragmented Espinal forest. The most effective way to preserve forest bird species in the Espinal forest seems to be by protecting the larger fragments of this relictual forest.

Early avian functional assemblages after fire, clearcutting, and post-fire salvage logging in North American forests

Increased demand for timber, the reduction in the available timber resources, more frequent and severe forest fires under a changing climate have increased the use of salvage logging in North American forests despite concerns regarding impacts on biodiversity and long-term forest productivity. We aimed to complement previous approaches that used bird species richness or individual abundance in salvage-logged habitats to assess the sustainability of this practice. We looked for commonalities in the taxonomic, functional and phylogenetic components of bird assemblages among these three post-disturbance habitats across a broad geographic range. We compiled six North American datasets selected from primary and grey literature that documented species composition of avian assemblages in habitats after recent fire, post-fire salvage logging and traditional logging. Our results revealed contrasting patterns of bird trait assemblage among burned, post-fire salvage and traditionally logged habitats. In salvage-logged habitats, taxonomic diversity, functional diversity, functional and phylogenetic redundancy were significantly lower than in both burned and traditionally logged habitats. The frequency of insectivores was significantly lower after salvage logging than after both fire and traditional logging. These findings suggest that cumulative disturbances have a negative effect on early assembly of bird communities. The outcomes of this study encourage further assessments, at landscape level, of salvage logging intensity, burn size and fire severity on bird functional structure to better plan for their conservation.

Avian assemblage along an urban gradient: diversity, abundance and richness

Diversity in avian assemblages of urban (UR), peri-urban (PE) and rural (RU) areas was studied to explore variations in the avian community dynamics in rural – urban gradient. For this purpose, sampling was done from September 2013 to August 2015. A total of 35 sites, each covering an area of 300 m2 were sampled by using point count method. At each site, randomly three points (minimally 5 m apart from each other) were selected to study the birds. According to data, species richness (F2, 32=47.18, P<0.001) varied significantly along a rural-urban gradient. A significant difference in avian density per sampling site (F2, 32=105.41, P<0.001) was also observed along urbanization gradient. In PE and RU areas, avian assemblages were more diverse than UR areas. Among avian guilds, omnivores were the most abundant in UR while insectivores in PE areas. Frugivores and carnivores were abundant in RU areas. Granivores were recorded in all habitats with similar diversity. A close association was recorded in bird density of RU and PE areas than UR areas. Bird species richness and diversity showed negative correlation with built area and positive correlation with vegetation cover in an area.